oc-server3/htdocs/lib/b2evo-captcha/b2evo_captcha.class.php
2012-05-09 20:05:43 +02:00

728 lines
22 KiB
PHP

<?php
/**
* PHP Class b2evo_captcha Version 1.3.1, released 27-Jan-2006
*
* a PHP Class for creating and testing captchas used in b2evolution
*
* Author : Ben Franske, ben@franske.com, http://ben.franske.com
*
* Based on hn_captcha Version 1.2 by Horst Nogajski, horst@nogajski.de
* - hn_captcha is a fork of ocr_captcha by Julien Pachet
*
* License: GNU GPL (http://www.opensource.org/licenses/gpl-license.html)
*
**/
/**
*
* changes in version 1.3.1:
* - removed unrequired double quotes
* - use function_exists() to check for some required functions
*
* changes in version 1.3:
* - modified for use in b2evolution and to make more of a standalone class:
* - stripped code so only image generation and testing remain
* - removed code for multiple attempts, one shot per image only (K.I.S.S.)
* - automatically select from multiple random fonts from the fonts folder
* - support for random captcha length
* - support for easily selecting valid characters and number of characters
* - added built-in garbage cleanup
* - support for case sensitive captchas
* - upgraded from rand() functions to mt_rand() functions
* - support for full md5 hashes instead of hash substrings
* - made it easier to drop in different image generation function
*
* changes in version 1.2:
* - added a new configuration-variable: secretposition
* - once more modified the function get_try(): generate a string of 32 chars length,
* where at secretposition is the number of current-try.
* Hopefully this is enough for hackprevention.
*
* changes in version 1.1:
* - added a new configuration-variable: maxrotation
* - added a new configuration-variable: secretstring
* - modified function get_try(): now ever returns a string of 16 chars
*
**/
/**
* License: GNU GPL (http://www.opensource.org/licenses/gpl-license.html)
*
* This program is free software;
*
* you can redistribute it and/or modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2 of the License,
* or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with this program;
* if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
**/
class b2evo_captcha
{
////////////////////////////////
//
// Default options, can be overridden from the calling code
//
/**
* Absolute path to a Tempfolder (with trailing slash!). This must be writeable for PHP and also accessible via HTTP, because the image will be stored there.
*
**/
var $tempfolder;
/**
* Absolute path to folder with TrueTypeFonts (with trailing slash!). This must be readable by PHP.
*
**/
var $TTF_folder;
/**
* The minimum number of characters to use for the captcha
* Set to the same as maxchars to use fixed length captchas
**/
var $minchars = 5;
/**
* The maximum number of characters to use for the captcha
* Set to the same as minchars to use fixed length captchas
**/
var $maxchars = 7;
/**
* The minimum font size to use
*
**/
var $minsize = 20;
/**
* The maximum font size to use
*
**/
var $maxsize = 30;
/**
* The maximum degrees a Char should be rotated. Set it to 30 means a random rotation between -30 and 30.
*
**/
var $maxrotation = 25;
/**
* Background noise On/Off (if is FALSE, a grid will be created)
*
**/
var $noise = TRUE;
/**
* This will only use the 216 websafe color pallette for the image.
*
**/
var $websafecolors = FALSE;
/**
* Outputs configuration values for testing
*
**/
var $debug = FALSE;
/**
* Filename of garbage collector counter which is stored in the tempfolder
*
**/
var $counter_filename = 'b2evo_captcha_counter.txt';
/**
* Prefix of captcha image filenames
*
**/
var $filename_prefix = 'b2evo_captcha_';
/**
* Number of captchas to generate before garbage collection is done
*
**/
var $collect_garbage_after = 100;
/**
* Maximum lifetime of a captcha (in seconds) before being deleted during garbage collection
*
**/
var $maxlifetime = 600;
/**
* Make all letters uppercase (does not preclude symbols)
*
**/
var $case_sensitive = TRUE;
////////////////////////////////
//
// Private options, these are fixed options
//
/**
* String of valid characters which may appear in the captcha
*
**/
var $validchars = 'abcdefghjkmnpqrstuvwxyz23456789?@#$%&*ABCDEFGHJKLMNPQRSTUVWXYZ23456789?@#$%&*';
/**
* Picture width
*
**/
var $lx;
/**
* Picture height
*
**/
var $ly;
/**
* JPEG Image quality
*
**/
var $jpegquality = 80;
/**
* Noise multiplier (number of characters gets multipled by this to define noise)
* Note: This doesn't quite make sense, do you really want less noise in a smaller captcha?
**/
var $noisefactor = 9;
/**
* Number of backgrond noise characters
*
**/
var $nb_noise;
/**
* Holds the list of possible fonts
*
**/
var $TTF_RANGE;
/**
* Holds the currently selected font filename
*
**/
var $TTF_file;
/**
* Holds the number of characters in the captcha
*
**/
var $chars;
var $public_K;
var $private_K;
/**
* Captcha filename
*
**/
var $filename;
/**
* Holds the version number of the GD-Library
*
**/
var $gd_version;
var $r;
var $g;
var $b;
////////////////////////////////
//
// CONSTRUCTOR
//
/**
* Extracts the config array and overrides default settings.
*
**/
function b2evo_captcha($config,$secure=TRUE)
{
// Test for GD-Library(-Version)
$this->gd_version = $this->get_gd_version();
if($this->gd_version == 0) die('There is no GD-Library-Support enabled. The b2evo captcha class cannot be used!');
if($this->debug) echo "\n<br>-b2evo-Captcha-Debug: The available GD-Library has major version ".$this->gd_version;
// extracts config array
if(is_array($config))
{
if($secure && (!function_exists('version_compare') || version_compare(phpversion(), '4.2.0', '< ')) && function_exists(array_key_exists))
{
if($this->debug) echo "\n<br>-b2evo-Captcha-Debug: Extracts Config-Array in secure-mode!";
$valid = get_class_vars(get_class($this));
foreach($config as $k=>$v)
{
if(array_key_exists($k,$valid)) $this->$k = $v;
}
}
else
{
if($this->debug) echo "\n<br>-b2evo-Captcha-Debug: Extracts Config-Array in unsecure-mode!";
foreach($config as $k=>$v) $this->$k = $v;
}
}
// check vars for min-max-chars and min-max-size
if($this->minchars > $this->maxchars)
{
$temp = $this->minchars;
$this->minchars = $this->maxchars;
$this->maxchars = $temp;
if($this->debug) echo "\n<br>-b2evo-Captcha-Debug: Arrghh! What do you think I mean with min and max? Switch minchars with maxchars.";
}
if($this->minsize > $this->maxsize)
{
$temp = $this->minsize;
$this->minsize = $this->maxsize;
$this->maxsize = $temp;
if($this->debug) echo "\n<br>-b2evo-Captcha-Debug: Arrghh! What do you think I mean with min and max? Switch minsize with maxsize.";
}
// check TrueTypeFonts
$this->TTF_RANGE = array('0');
if ($handle = opendir($this->TTF_folder)) {
$i=0;
while (false !== ($file = readdir($handle))) {
//You could add a regex to this if to make sure the files are all *.ttf
if ($file != '.' && $file != '..') {
if (is_file($this->TTF_folder . $file)) {
$this->TTF_RANGE[$i]=$file;
if($this->debug) echo "\n<br>-b2evo-Captcha-Debug: Found font file (".$file.')';
}
}
}
closedir($handle);
}
if(is_array($this->TTF_RANGE))
{
if($this->debug) echo "\n<br>-b2evo-Captcha-Debug: Checking given TrueType-Array! (".count($this->TTF_RANGE).')';
$temp = array();
foreach($this->TTF_RANGE as $k=>$v)
{
if(is_readable($this->TTF_folder.$v)) $temp[] = $v;
}
$this->TTF_RANGE = $temp;
if($this->debug) echo "\n<br>-b2evo-Captcha-Debug: Valid TrueType-files: (".count($this->TTF_RANGE).')';
if(count($this->TTF_RANGE) < 1) die('No Truetype fonts available for the CaptchaClass.');
}
else
{
if($this->debug) echo "\n<br>-b2evo-Captcha-Debug: Check given TrueType-File! (".$this->TTF_RANGE.')';
if(!is_readable($this->TTF_folder.$this->TTF_RANGE)) die('No Truetypefont available for the b2evo captcha class.');
}
// select first TrueTypeFont
$this->change_TTF();
if($this->debug) echo "\n<br>-b2evo-Captcha-Debug: Set current TrueType-File: (".$this->TTF_file.")";
// get number of noise-chars for background if is enabled
$this->nb_noise = $this->noise ? ($this->chars * $this->noisefactor) : 0;
if($this->debug) echo "\n<br>-b2evo-Captcha-Debug: Set number of noise characters to: (".$this->nb_noise.')';
// seed the random number generator if less than php 4.2.0
if( !function_exists('version_compare') || version_compare(phpversion(), '4.2.0', '< ') )
{
mt_srand((double)microtime()*1000000);
}
// specify counter-filename
if($this->debug) echo "\n<br>-Captcha-Debug: The counterfilename is (".$this->tempfolder.$this->counter_filename.')';
// retrieve last counter-value
$test = $this->txt_counter($this->tempfolder.$this->counter_filename);
// set and retrieve current counter-value
$counter = $this->txt_counter($this->tempfolder.$this->counter_filename,TRUE);
// check if counter works correct
if(($counter !== FALSE) && ($counter - $test == 1))
{
// Counter works perfect, =:)
if($this->debug) echo "\n<br>-Captcha-Debug: Current counter-value is ($counter). Garbage-collector should start at (".$this->collect_garbage_after.')';
// check if garbage-collector should run
if($counter >= $this->collect_garbage_after)
{
// Reset counter
if($this->debug) echo "\n<br>-Captcha-Debug: Reset the counter-value. (0)";
$this->txt_counter($this->tempfolder.$this->counter_filename,TRUE,0);
// start garbage-collector
$this->garbage_collector_error = $this->collect_garbage() ? FALSE : TRUE;
if($this->debug) echo "\n<br>-Captcha-Debug: ERROR! SOME TRASHFILES COULD NOT BE DELETED!";
}
}
else
{
// Counter-ERROR!
if($this->debug) echo "\n<br>-Captcha-Debug: ERROR! NO COUNTER-VALUE AVAILABLE!";
}
}
////////////////////////////////
//
// PUBLIC METHODS
//
/**
* Generates a captcha image and returns the complete path to the image
*
**/
function get_b2evo_captcha()
{
$this->make_captcha();
if($public=='') $public = $this->public_key;
return str_replace($_SERVER['DOCUMENT_ROOT'],'',$this->tempfolder).$this->filename_prefix.$public.'.jpg';
}
/**
*
* Validates submission and returns result
* Returns 0 = invalid sumbit | 1 = valid submit
*
**/
function validate_submit($image,$attempt)
{
$correct_hash = substr($image,-36,32);
if($this->case_sensitive==0) $attempt = strtoupper($attempt);
if($this->check_captcha($correct_hash,$attempt))
{
if($this->debug) echo "\n<br>-Captcha-Debug: Validating submitted form returns: (1)";
return 1;
}
else
{
if($this->debug) echo "\n<br>-Captcha-Debug: Validating submitted form returns: (0)";
return 0;
}
}
////////////////////////////////
//
// PRIVATE METHODS
//
/** @private **/
function make_captcha($private_key='')
{
if($private_key=='') $private_key = $this->generate_keypair();
// set dimension of image
$this->lx = (strlen($private_key) + 1) * (int)(($this->maxsize + $this->minsize) / 1.5);
$this->ly = (int)(2.4 * $this->maxsize);
if($this->debug) echo "\n<br>-b2evo-Captcha-Debug: Set image dimension to: (".$this->lx.' x '.$this->ly.')';
if($this->debug) echo "\n<br>-Captcha-Debug: Generate private key: ($private_key)";
// set number of noise-chars for background if is enabled
$this->nb_noise = $this->noise ? (strlen($private_key) * $this->noisefactor) : 0;
if($this->debug) echo "\n<br>-b2evo-Captcha-Debug: Set number of noise characters to: (".$this->nb_noise.')';
// create Image and set the apropriate function depending on GD-Version & websafecolor-value
if($this->gd_version >= 2 && !$this->websafecolors)
{
$func1 = 'imagecreatetruecolor';
$func2 = 'imagecolorallocate';
}
else
{
$func1 = 'imageCreate';
$func2 = 'imagecolorclosest';
}
$image = $func1($this->lx,$this->ly);
if($this->debug) echo "\n<br>-Captcha-Debug: Generate ImageStream with: ($func1())";
if($this->debug) echo "\n<br>-Captcha-Debug: For colordefinitions we use: ($func2())";
// Set Backgroundcolor
$this->random_color(224, 255);
$back = @imagecolorallocate($image, $this->r, $this->g, $this->b);
@ImageFilledRectangle($image,0,0,$this->lx,$this->ly,$back);
if($this->debug) echo "\n<br>-Captcha-Debug: We allocate one color for Background: (".$this->r.'-'.$this->g.'-'.$this->b.')';
// allocates the 216 websafe color palette to the image
if($this->gd_version < 2 || $this->websafecolors) $this->makeWebsafeColors($image);
// fill with noise or grid
if($this->nb_noise > 0)
{
// random characters in background with random position, angle, color
if($this->debug) echo "\n<br>-Captcha-Debug: Fill background with noise: (".$this->nb_noise.')';
for($i=0; $i < $this->nb_noise; $i++)
{
$size = intval(mt_rand((int)($this->minsize / 2.3), (int)($this->maxsize / 1.7)));
$angle = intval(mt_rand(0, 360));
$x = intval(mt_rand(0, $this->lx));
$y = intval(mt_rand(0, (int)($this->ly - ($size / 5))));
$this->random_color(160, 224);
$color = $func2($image, $this->r, $this->g, $this->b);
$text = chr(intval(mt_rand(45,250)));
@ImageTTFText($image, $size, $angle, $x, $y, $color, $this->change_TTF(), $text);
}
}
else
{
// generate grid
if($this->debug) echo "\n<br>-Captcha-Debug: Fill background with x-gridlines: (".(int)($this->lx / (int)($this->minsize / 1.5)).')';
for($i=0; $i < $this->lx; $i += (int)($this->minsize / 1.5))
{
$this->random_color(160, 224);
$color = $func2($image, $this->r, $this->g, $this->b);
@imageline($image, $i, 0, $i, $this->ly, $color);
}
if($this->debug) echo "\n<br>-Captcha-Debug: Fill background with y-gridlines: (".(int)($this->ly / (int)(($this->minsize / 1.8))).')';
for($i=0 ; $i < $this->ly; $i += (int)($this->minsize / 1.8))
{
$this->random_color(160, 224);
$color = $func2($image, $this->r, $this->g, $this->b);
@imageline($image, 0, $i, $this->lx, $i, $color);
}
}
// generate Text
if($this->debug) echo "\n<br>-Captcha-Debug: Fill forground with chars and shadows: (".$this->chars.')';
for($i=0, $x = intval(mt_rand($this->minsize,$this->maxsize)); $i < strlen($private_key); $i++)
{
$text = substr($private_key, $i, 1);
$angle = intval(mt_rand(($this->maxrotation * -1), $this->maxrotation));
$size = intval(mt_rand($this->minsize, $this->maxsize));
$y = intval(mt_rand((int)($size * 1.5), (int)($this->ly - ($size / 7))));
$this->random_color(0, 127);
$color = $func2($image, $this->r, $this->g, $this->b);
$this->random_color(0, 127);
$shadow = $func2($image, $this->r + 127, $this->g + 127, $this->b + 127);
@ImageTTFText($image, $size, $angle, $x + (int)($size / 15), $y, $shadow, $this->change_TTF(), $text);
@ImageTTFText($image, $size, $angle, $x, $y - (int)($size / 15), $color, $this->TTF_file, $text);
$x += (int)($size + ($this->minsize / 5));
}
@ImageJPEG($image, $this->get_filename(), $this->jpegquality);
$res = file_exists($this->get_filename());
if($this->debug) echo "\n<br>-Captcha-Debug: Save Image with quality [".$this->jpegquality.'] as ('.$this->get_filename().') returns: ('.($res ? 'TRUE' : 'FALSE').')';
@ImageDestroy($image);
if($this->debug) echo "\n<br>-Captcha-Debug: Destroy Imagestream.";
if(!$res) die('Unable to save captcha-image.');
}
/** @private **/
function makeWebsafeColors(&$image)
{
//$a = array();
for($r = 0; $r <= 255; $r += 51)
{
for($g = 0; $g <= 255; $g += 51)
{
for($b = 0; $b <= 255; $b += 51)
{
$color = imagecolorallocate($image, $r, $g, $b);
//$a[$color] = array('r'=>$r,'g'=>$g,'b'=>$b);
}
}
}
if($this->debug) echo "\n<br>-Captcha-Debug: Allocate 216 websafe colors to image: (".imagecolorstotal($image).')';
//return $a;
}
/** @private **/
function random_color($min,$max)
{
$this->r = intval(mt_rand($min,$max));
$this->g = intval(mt_rand($min,$max));
$this->b = intval(mt_rand($min,$max));
//echo ' ('.$this->r.'-'.$this->g.'-'.$this->b.') ';
}
/** @private **/
function change_TTF()
{
if(is_array($this->TTF_RANGE))
{
$key = array_rand($this->TTF_RANGE);
$this->TTF_file = $this->TTF_folder.$this->TTF_RANGE[$key];
}
else
{
$this->TTF_file = $this->TTF_folder.$this->TTF_RANGE;
}
return $this->TTF_file;
}
/** @private **/
function check_captcha($correct_hash,$attempt)
{
// when check, destroy picture on disk
if(file_exists($this->get_filename($correct_hash)))
{
$res = @unlink($this->get_filename($correct_hash)) ? 'TRUE' : 'FALSE';
if($this->debug) echo "\n<br>-Captcha-Debug: Delete image (".$this->get_filename($correct_hash).") returns: ($res)";
}
else
return FALSE;
$res = (md5($attempt)===$correct_hash) ? 'TRUE' : 'FALSE';
if($this->debug) echo "\n<br>-Captcha-Debug: Comparing public with private key returns: ($res)";
return $res == 'TRUE' ? TRUE : FALSE;
}
/** @private **/
function get_filename($public='')
{
if($public=='') $public=$this->public_key;
return $this->tempfolder.$this->filename_prefix.$public.'.jpg';
}
/** @private **/
function get_filename_url($public="")
{
if($public=='') $public = $this->public_key;
return str_replace($_SERVER['DOCUMENT_ROOT'],'',$this->tempfolder).$this->filename_prefix.$public.'.jpg';
}
/** @private **/
function get_gd_version()
{
if (!function_exists('imagejpeg')) {
$gd_version_number = 0;
} else {
static $gd_version_number = null;
if($gd_version_number === null)
{
ob_start();
phpinfo(8);
$module_info = ob_get_contents();
ob_end_clean();
if(preg_match("/\bgd\s+version\b[^\d\n\r]+?([\d\.]+)/i", $module_info, $matches))
{
$gd_version_number = $matches[1];
}
else
{
$gd_version_number = 0;
}
}
}
return $gd_version_number;
}
// this is where the actual text and public hash is generated and stored
function generate_keypair()
{
$key = '';
$this->chars = mt_rand($this->minchars,$this->maxchars);
for($i=0; $i < $this->chars; $i++) {
$key .= $this->validchars{mt_rand(0,strlen($this->validchars))};
}
if($this->case_sensitive==0) $key = strtoupper($key);
$this->public_key = md5($key);
if($this->debug) echo "\n<br>-Captcha-Debug: Generate Keys, private key is: (".$key.')';
if($this->debug) echo "\n<br>-Captcha-Debug: Generate Keys, public key is: (".$this->public_key.')';
return $key;
}
//Store/Retrieve a counter-value in/from a textfile. Optionally count it up or store a (as third param) specified value.
// Returns counter-value
function txt_counter($filename,$add=FALSE,$fixvalue=FALSE)
{
if(is_file($filename) ? TRUE : touch($filename))
{
if(is_readable($filename) && is_writable($filename))
{
$fp = @fopen($filename, 'r');
if($fp)
{
$counter = (int)trim(fgets($fp));
fclose($fp);
if($add)
{
if($fixvalue !== FALSE)
{
$counter = (int)$fixvalue;
}
else
{
$counter++;
}
$fp = @fopen($filename, 'w');
if($fp)
{
fputs($fp,$counter);
fclose($fp);
return $counter;
}
else return FALSE;
}
else
{
return $counter;
}
}
else return FALSE;
}
else return FALSE;
}
else return FALSE;
}
// Scanns the tempfolder for jpeg-files with nameprefix used by the class and trash them if they are older than maxlifetime.
function collect_garbage()
{
$OK = FALSE;
$captchas = 0;
$trashed = 0;
if($handle = @opendir($this->tempfolder))
{
$OK = TRUE;
while(false !== ($file = readdir($handle)))
{
if(!is_file($this->tempfolder.$file)) continue;
// check for name-prefix, extension and filetime
if(substr($file,0,strlen($this->prefix)) == $this->prefix)
{
if(strrchr($file, '.') == '.jpg')
{
$captchas++;
if((time() - filemtime($this->tempfolder.$file)) >= $this->maxlifetime)
{
$trashed++;
$res = @unlink($this->tempfolder.$file);
if(!$res) $OK = FALSE;
}
}
}
}
closedir($handle);
}
if($this->debug) echo "\n<br>-Captcha-Debug: There are ($captchas) captcha-images in tempfolder, where ($trashed) are seems to be lost.";
return $OK;
}
} // END CLASS b2evo_captcha
?>